This invention relates to a multi-event notification system for monitoring pre-selected critical pressure points, as a function of pressure in a lapsed time, on the feet of persons who have been diagnosed as having diminished sensation in the feet, especially diabetes mellitus.
There have been a number of inventions which have been specifically aimed at problems related to diabetes. However, most of these inventions have related to devices for monitoring conditions indicating the onset or existence of insulin shock. Physiological conditions associated with insulin shock include lowered skin resistance, a drop in body temperature, a reduced ability to respond to light changes (eye pupil dilation lag), and, in heavy shock, increased heart beat, labored breathing, and convulsions. If allowed to develop, such shock can lead to a heart attack and death. The prior art devices have primarily been aimed at detecting any number of these various physiological conditions. Specifically, U.S. Pat. No. 4,365,639 discloses a perspiration indicating alarm for diabetics. In this device any increase in perspiration is detected and signals an alarm. U.S. Pat. No. 4,178,916 to a diabetic insulin alarm system discloses a system that is worn by a diabetic person which responds to the wearer's abnormal skin resistance or temperature and signals this indication to the wearer. U.S. Pat. No. 4,073,292 to a control apparatus for the automatic treatment of diabetes discloses an invention for monitoring the body's sugar level during a given period and injecting suitable doses of insulin to suppress any excess amount of glucose.
The present invention is directed at another significant problem encountered by people suffering from diabetes. Those persons who have diabetes in such severity as to have poor sensation in the lower extremities with either partial or total loss of feeling currently have no means, other than visible observation, of determining whether a skin ulceration is occurring in skin of the foot. This problem is further compounded because ulcers or open wounds are very slow to heal in the diabetic where metabolism and blood circulation is poor. Once an ulcer or open wound has been discovered, the diabetic is required to stay off the foot or feet, that is, remove the pressure from where the wound is located. In some situations this requires days, weeks, or even months. The duration of time which the patient must remain off of his feet is dependent upon the rate of healing of the ulcer which in turn is dependent upon the blood flow to the damaged area.
Such ulcers or open wounds are almost invariably the result of pressure applied to a particular point on the front through standing or walking over a period of time. Since a diabetic has only partial or no feeling in the feet, the point at which such damage occurs is not known to the diabetic at the time of occurrence. There is no reliable notification system in existence today that can alert the diabetic that such damage is about to occur. If the damage is to be prevented, the diabetic must remove the pressure from the area where the ulcer or wound is about to occur.
While there have been sensors developed which measure the forces exerted by the human body during such movements as walking, jogging, and orthopedic testing, none have been directed toward the particular problems encountered by the diabetic who may experience low levels of pressure over extended time periods. U.S. Pat. No. 4,426,884 discloses an invention which relates to a sensor for sensing foot pressures and is incorporated herein by reference.
The instant invention is a reliable, accurate, mobile, self-contained, automatic, multi-event twenty-four hour per day alert system for the diabetic. The system is inconspicuously attachable to the person of the diabetic for notifying the diabetic that the pressure/time threshold is about to be reached and that if pressure is not removed an ulcer or wound could occur. The present invention serves a significant preventative function and prevents much human suffering.